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Category Archives: Sun

This image from the Solar Dynamics Observatory shows the X6.9 solar flare of Aug. 9, 2011 near the western limb (right edge) of the sun. CREDIT: NASA/SDO/Weather.com

Solar flares like the huge one that erupted on the sun early today (Aug. 9) will only become more common as our sun nears its maximum level of activity in 2013, scientists say.

Tuesday’s flare was the most powerful sun storm since 2006, and was rated an X6.9 on the three-class scale for solar storms (X-Class is strongest, with M-Class in the middle and C-Class being the weakest).

Flares such as this one could become the norm soon, though, as our sun’s 11-year cycle of magnetic activity ramps up, scientists explained. The sun is just coming out of a lull, and scientists expect the next peak of activity in 2013. The current cycle, called Solar Cycle 24, began in 2008.

“We still are on the upswing with this recent burst of activity,” said Phil Chamberlin, a solar scientist at NASA’s Goddard Space Flight Center in Greenbelt, Md., who is a deputy project scientist for the agency’s Solar Dynamics Observatory, a sun-studying satellite that launched in February 2010. “We could definitely in the next year or two see more events like this; there’s a potential to see larger events as well.”

A more active sun

Earth got lucky with the most recent flare, which wasn’t pointed directly at Earth; therefore, it didn’t send the brunt of its charged particles toward us, but out into space. However, we may not be so fortunate in the future, experts warned.

“We’re in the new cycle, it is building and we’ll see events like this one,” said Joe Kunches, a space scientist with the National Oceanic and Atmospheric Administration (NOAA)’s Space Weather Prediction Center. “They’ll be much more commonplace and we’ll get more used to them.”

Spacecraft such as the Solar Dynamics Observatory (SDO), which recorded amazing videos of the Aug. 9 solar flare, and other observatories will be vital in monitoring the sun during its active phase, researchers said.

How sun storms form

Storms brew on the sun when pent-up energy from tangled magnetic field lines is released in the form of light, heat and charged particles. This can create a brightening on the sun called a flare, and is also often accompanied by the release of a cloud of plasma called a coronal mass ejection (CME).

These ejections are the part we Earthlings have to worry about.

As the CME careens through space, it can send a horde of charged particles toward our planet that can damage satellites, endanger astronauts in orbit, and interfere with power systems, communications and other infrastructure on the ground.

“We’re well aware of the difficulties and challenges,” Kunches told SPACE.com. “We know more about the sun than we ever have.”

Can we predict solar storms?

When a big storm occurs, the Space Weather Prediction Center releases a warning to the U.S. Department of Homeland Security, emergency managers and agencies responsible for protecting power grids. Then power grids can distribute power and reduce their loads to protect themselves.

Satellite and power companies are also trying to design technology that can better withstand the higher radiation loads unleashed by solar storms.

Still, scientists would like to offer more advanced warnings when big storms are headed our way.

“We’re being reactive, we’re not being proactive,” Chamberlin said. “We don’t know how to predict these things, which would be nice.”

Chamberlin said solar science has come a long way in recent years, though, and the goal of SDO and other NASA projects is to improve our understanding of the sun and our ability to forecast space weather.

You can follow SPACE.com senior writer Clara Moskowitz on Twitter @ClaraMoskowitz. Follow SPACE.com for the latest in space science and exploration news on Twitter @Spacedotcom and on Facebook.

Ever since the Voyager 2 data confirmed the nonsymmetrical shape of the solar system scientists have pondered its cause (i). In summary, the edge of the heliosphere (the place where the solar wind slows to sub sonic speeds) appears to be 1.2 billion kilometers shorter on the south side of the solar system (and in the general direction of the winter solstice, the direction of Voyager 2), than it is on the edge of the planetary plane (where Voyager 1 exited approximately a year earlier). This indicates the heliosphere is not a sphere at all but a bullet shape. More data is required to determine the exact shape in all directions.

The initial explanation was there must be some sort of gas cloud pressing against one side of our solar system. While this hypothesis is plausible there is another possibility that deserves consideration; stellar wind.

The sun’s solar winds are primarily driven by its magnetic field. When magnetic storms arise on the sun it produces coronal mass ejections (CME’s), which are like waves or ripples on the solar wind. The solar wind is constantly pushing on the daylight side of the earth’s magnetosphere squashing it in a pattern similar to the way the sun’s magnetic field seems to be squashed where Voyager 2 exited the solar system. Thus it is possible that the dented solar system might be due to the same type of cause; stellar winds from a not too distant star.

Some indication of this might reside in the data recently received by NASA’s sun-focused STEREO spacecraft. The twin STEREO spacecraft were launched in 2006 into earth’s orbit about the sun to obtain stereo pictures of the sun’s surface and to measure magnetic fields and ion fluxes associated with solar explosions. Between June and October 2007, the STEREO spacecraft detected atoms “originating from the same spot in the sky: the shock front and the heliosheath beyond, where the sun plunges through the interstellar medium”, and found “energetic neutral particles from beyond the heliosphere” that are moving toward the sun (ii). While this might be due to other causes such as “charge exchange between hot ions and neutral atoms” as hypothesized by scientists at UC Berkeley, it may also indicate the source of the asymmetrical solar system is due to the stellar wind from another star rather than an interstellar gas cloud. More data is needed and should be forthcoming with the pending launch of the Interstellar Boundary Explorer (IBEX), due to begin receiving data some time in the next year.

A little tough to understand, but this diagram shows where the solar eclipse in May of 2012 can be experienced

An annular solar eclipse will take place on May 20, 2012 with a magnitude of 0.9439. For more about what the magnitude of a solar eclipse is, please click here. A solar eclipse occurs when the Moon passes between Earth and the Sun, thereby totally or partially obscuring the image of the Sun for a viewer on Earth. An annular solar eclipse occurs when the Moon’s apparent diameter is smaller than the Sun, causing the sun to look like an annulus (ring), blocking most but not all of the Sun’s light. An annular eclipse appears as a partial eclipse over a region thousands of kilometres wide.

The annular phase will be visible from the Chinese coast, the south of Japan, and the western part of the United States and Canada. Cities such as Albuquerque, New Mexico and Redding, Ca. will see this eclipse. Guangzhou, China, Tokyo and Albuquerque will be on the central path. Its maximum will occur in the North Pacific, south of the Aleutian islands for 5 min and 46.3 s, and finish in the western United States.

It will be the first central eclipse of the 21st century in the Lower 48, and also the first annular eclipse visible here since the solar eclipse of May 10, 1994.